Monthly Archives for October 2015

YOU HAVE TIL HALLOWEEN to Help us do science! I’ve teamed up with researcher Paige Brown Jarreau to create a survey of CauseScience readers. By participating, you’ll be helping me improve CauseScience and contributing to SCIENCE on blog readership. You will also get FREE science art from Paige’s Photography for participating, as well as a chance to win a t-shirt or a $50.00 Amazon gift card (100 available).

International Day of the Girl is celebrated in October and celebrates and highlights opportunities for girls across the globe. Over 47% of the workforce is women, and we all need to be celebrated! Women in STEM fields should be particularly celebrated, as they are underrepresented and often face discrimination working in STEM fields. Teza technologies has provided CauseScience with the infographic below to draw attention to women in STEM fields during the month of October, take a look!

You’ve probably seen today’sheadlines, about the fact that processed meat has been classified as a ‘definite’ cause of cancer. And red meat is a ‘probable’ cause.

The decision – coordinated by a respected international body – has been so highly anticipated by the media that speculation about the announcement has been building since last week.

But a link between certain types of meat and some forms of cancer – notably bowel cancer – isn’t ‘new’ news – the evidence has been building for decades, and is supported by a lot of careful research.

Nevertheless, today’s announcement is significant. It comes from the International Agency for Research on Cancer (IARC) – a group of international experts who scrutinise the overall evidence – in this case more than 800 studies – on how likely certain things are to cause cancer. Their decisions carry a lot of clout, especially with governments and regulators.

But what does the finding – published here in the Lancet Oncology – mean in practice? How much meat is it sensible to eat? And how many cases of cancer are linked to meat consumption?

In this post, we’ll look at what IARC’s classification actually means, how red and processed meat affect cancer risk, and the likely size of this effect.

But before we move on, let’s be clear: yes, a prolonged high-meat diet isn’t terribly good for you. But a steak, bacon sandwich or sausage bap a few times a week probably isn’t much to worry about. And overall the risks are much lower than for other things linked to cancer – such as smoking.

What are ‘red’ and ‘processed’ meat?

First, let’s clear up some definitions.

‘Red’ meat is (as you might expect), any meat that’s a dark red colour before it’s cooked – this obviously means meats like beef and lamb, but also includes pork.

‘Processed’ meat is meat that’s not sold fresh, but instead has been cured, salted, smoked, or otherwise preserved in some way (so things like bacon, sausages, hot dogs, ham, salami, and pepperoni). But this doesn’t include fresh burgers or mince.

Both of these types of meat are distinct from ‘white’ meats, like fresh chicken or turkey, and fish (neither of which appear to increase your risk of cancer).

(There’s also growing evidence for a possible link to both stomach and pancreatic cancers, but this seems to be less clear cut than the link to bowel cancer.)

The most convincing overview of the evidence of a link to bowel cancer comes from a 2011 analysis by researchers at the WCRF, who combined the results of a number of previous studies, to try to get a clear sense of the overall picture.

They were able to group the data according to those who ate the most red and processed meat and those who ate the least. A key finding from the WCRF analysis is that red meat and processed meat aren’t equally harmful: processed meat is more strongly linked to bowel cancer than red meat.

The results showed that those who ate the most processed meat had around a 17 per cent higherrisk of developing bowel cancer, compared to those who ate the least.

‘17 per cent’ sounds like a fairly big number – but this is a ‘relative’ risk, so let’s put it into perspective, and convert it to absolute numbers. Remember these are all ball-park figures – everyone’s risk will be different as there are many different factors at play.

We know that, out of every 1000 people in the UK, about 61 will develop bowel cancer at some point in their lives. Those who eat the lowest amount of processed meat are likely to have a lower lifetime risk than the rest of the population (about 56 cases per 1000 low meat-eaters).

If this is correct, the WCRF’s analysis suggests that, among 1000 people who eat the most processed meat, you’d expect 66 to develop bowel cancer at some point in their lives – 10 more than the group who eat the least processed meat.

How does red and processed meat cause cancer?

Researchers are still trying to pin down exactly how red and processed meat cause cells to become cancerous, but the main culprits seem to be certain chemicals found in the meat itself.

In red meat, the problems seem to start when a chemical called haem – part of the red pigment in the blood, haemoglobin – is broken down in our gut to from a family of chemicals called N-nitroso compounds. These have been found to damage the cells that line the bowel, so other cells in the bowel lining have to replicate more in order to heal. And it’s this ‘extra’ replication that can increase the chance of errors developing in the cells’ DNA – the first step on the road to cancer.

On top of this, processed red meats contain chemicals that generate N-nitroso compounds in the gut, such as nitrite preservatives.

Cooking meat at high temperatures, such as grilling or barbequing, can also create chemicals in the meat that may increase the risk of cancer. These chemicals are generally produced in higher levels in red and processed meat compared to other meats.

So despite what you may hear, it isn’t about the quality of the meat, or whether it’s from the local butcher or your supermarket. The evidence so far suggests that it’s probably the processing of the meat, or chemicals naturally present within it, that increases cancer risk.

What does this decision from IARC mean?

Whatever the underlying mechanism, there’s now sufficient evidence for IARC to rule that processed meat ‘definitely’ causes cancer, and that red meat ‘probably’ causes cancer. But to really understand what this means (and doesn’t mean), you need to know a bit about IARC’s categories.

When IARC assesses the evidence on a particular cancer risk, it assigns it to one of several groups, which – as the graphic below shows – represent how confident they are that it causes cancer in people.

Processed meat has been classified as a ‘definite’ cause of cancer (or Group 1 carcinogen) – the same group that includes smoking and alcohol. And red meat is a ‘probable’ cause of cancer (or a Group 2a carcinogen) – the same group as shift work. While this may sound alarming, it’s important to remember that these groups show how confident IARC is that red and processed meat cause cancer, not how much cancer they cause.

IARC does ‘hazard identification’, not ‘risk assessment’. That sounds quite technical, but what it means is that IARC isn’t in the business of telling us how potent something is in causing cancer – only whether it does so or not.

To take an analogy, think of banana skins. They definitely can cause accidents – but in practice this doesn’t happen very often (unless you work in a banana factory). And the sort of harm you can come to from slipping on a banana skin isn’t generally as severe as, say, being in a car accident.

But under a hazard identification system like IARC’s, ‘banana skins’ and ‘cars’ would come under the same category – they both definitely do cause accidents.

– Professor David Phillips

To put things in perspective, let’s look at how red and processed meat stack up against smoking:

In 2011, scientists estimated that around 3 in every hundred cancers in the UK were due to eating too much red and processed meat (that’s around 8,800 cases every year). This compares against 64,500 cases every year caused by smoking (or 19 per cent of all cancers).

So what does this mean for mealtimes?

Does red and processed meat still have a place in a healthy diet?

None of this means that a single meat-based meal is ‘bad for you’. What it does mean is that regularly eating large amounts of red and processed meat, over a long period of time, is probably not the best approach if you’re aiming to live a long and healthy life. Meat is fine in moderation – it’s a good source of some nutrients such as protein, iron and zinc. It’s just about being sensible, and not eating too much, too often.

So how much is a ‘sensible’ amount of meat? This is a much trickier question to answer. The evidence so far doesn’t point to a particular amount that’s, in terms of cancer risk, likely to be ‘too much’. All we can say is that on the whole, the risk is lower the less you eat. Based on a range of health considerations, the Government advises people who eat more than 90g (cooked weight) of red and/or processed meat a day should cut down to 70g or less.

But what do these portions actually look like?

So if you’re someone who has a very meaty diet, and you’re worried about cancer, you may want to think about cutting down. That doesn’t mean you need to start stocking up on tofu, unless you want to, it just means trying to eat smaller and fewer portions (by adding in more vegetables, beans and pulses – remember the eatwell plate?), or choosing chicken or fish instead. As we said above, there’s no strong evidence linking fresh white meats such as chicken, turkey, or fish to any types of cancer.

So our advice on diet stays the same: eat plenty of fibre, fruit and vegetables; cut back on red and processed meat, and salt; and limit your alcohol intake. It might sound boring but it’s true: healthy living is all about moderation.

Help us do science! I’ve teamed up with researcher Paige Brown Jarreau to create a survey of CauseScience readers. By participating, you’ll be helping me improve CauseScience and contributing to SCIENCE on blog readership. You will also get FREE science art from Paige’s Photography for participating, as well as a chance to win a t-shirt or a $50.00 Amazon gift card (100 available).

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What will humanity look like in 1000 years? Watch as we cover some cutting-edge innovations happening today. Thanks to the National Geographic Channel for sponsoring this video!

DONT FORGET – Help us do science! The survey should only take 5-10 minutes to complete. You can find the survey here: http://bit.ly/mysciblogreaders. By participating, you’ll be helping me improve CauseScience and contributing to SCIENCE on blog readership. You will also get FREE science art from Paige’s Photography for participating, as well as a chance to win a t-shirt or a $50.00 Amazon gift card (100 available).

DONT FORGET – Help us do science! The survey should only take 5-10 minutes to complete. You can find the survey here: http://bit.ly/mysciblogreaders. By participating, you’ll be helping me improve CauseScience and contributing to SCIENCE on blog readership. You will also get FREE science art from Paige’s Photography for participating, as well as a chance to win a t-shirt or a $50.00 Amazon gift card (100 available).

In case you didn’t see the media coverage of an abstract from the recent meeting of the American Society of Human Genetics in Baltimore, Maryland (see Nature News stories here), an abstract presented preliminary data in the search for the genetic roots of homosexuality in human twins. Obviously this scientific presentation, and the press release about it from the conference, generated excitement, skepticism, and now controversy. Nature has a terrific editorial this week examining how this was a failure in science communication. Scientific conferences and meetings are meant to be a place to present preliminary, controversial, and incomplete studies to scientific peers to get feedback, ideas, and promote the work being done. Criticism of the work and experiments are always a part of this process, but where do we draw the line?

A few critics went so far as to argue that the authors should not have presented such preliminary work at the meeting. And at least one suggested that the authors could have provided preprints of their study when presenting it. These arguments seem to misunderstand the traditional, and still useful and relevant, role of such gatherings. Studies with small sample sizes and controversial methods are presented at conferences all the time, and many scientists already fear being scooped when they present even a bit of their data.

One might wonder how so much media coverage was generated from a scientific conference abstract, and the answer is that the conference used the abstract in a press release, unfortunately titled, ‘Epigenetic Algorithm Accurately Predicts Male Sexual Orientation.’ While this may represent the science, it opens the door for misinterpretation by non-scientists that never saw the data presented. This failure in science communication has a remedy, and it involves being careful with press releases of unpublished, non-peer-reviewed science, especially on topics that could be ‘misused’ or misinterpreted by the press.

The genetics of homosexuality is a subject that will always find media coverage, partly because of the societal interest in the topic. Neither the scientists nor the conference organizers can be held responsible for how some in the media chose to write about the study. But both could have done more to get the right message across.

NBC News reports on the developing Hurricane Patricia, which is now the strongest hurricane ever recorded and is on a path to hit Mexico. Other meteorologists commented on the super storm on social media, including fan favorite Jim Cantore who took a somewhat dramatic tone (tweets above and below).

Hurricane Patricia became the strongest storm ever measured on the planet early Friday, with experts warning it could trigger 40-foot waves along Mexico’s coast and “life-threatening” flash flooding.

Several million residents were told to prepare for the “worst-case scenario” as Patricia was expected to race ashore on Mexico’s Pacific coast late Friday afternoon or early evening. The tourist magnets of Puerto Vallarta and Manzanillo were directly in the Category 5 storm’s projected path.

Featuring 200 mph winds, the U.S. National Hurricane Center described Patricia the “strongest hurricane on record” in the Atlantic and eastern North Pacific Basins.

[tweet https://twitter.com/JimCantore/status/657483877380935680]

What did climate scientists warn us would be a consequence of climate change? Unprecedented extreme weather including deadly hurricanes??…. Right, that one. Climate change is real, and we are seeing the consequences NOW. We need to take drastic measures to try to curb climate change or more storms like this and worse are in our near future. Tell our world leaders that climate change needs to be a priority before the Paris Climate Summit – https://www.climaterealityproject.org